An Arabic author of math texts, I am often called "The Reckoner from Egypt."
My book Book of Algebra contained a total of 69 problems and was a commentary on the great al-Khowarizmi's treatise.
I developed a special "calculus of radicals" that allowed one to add and subtract square roots easily.
In my Book of Rare Things in the Art of Calculation, my major contribution was the use of irrational coefficients in indeterminate equations.
My text Book of Algebra strongly influenced Fibonacci's writing of his Liber Abaci, who reproduced (i.e. plagarized) 29 of my problems.
Abu Kamil (circa 850--930)